Veterinary Services

A two-month-old Beef Shorthorn cross calf submitted from a beef suckler unit in Perthshire had a three-day history of depression, inappetance and pyrexia prior to death. It had displayed melaena and eventually fresh blood in the faeces.  Necropsy revealed generalised haemorrhages affecting most of the carcase. The entire intestinal tract had coalesced due to marked intra-mesenteric haemorrhage and there were numerous haemorrhages along both the serosal and luminal surfaces of the intestines. The limb joints showed evidence of intra-articular haemorrhage and the brain revealed showed intra-cranial haemorrhage.  Bacterial culture yielded growths of E.coli from throughout the carcase. Neuropathology confirmed the presence of several perivascular haemorrhages while tissue histopathology found marked widespread haemorrhage and peritonitis, with Payers patch depletion and necrosis in the small intestine. Bovine Virus Diarrhoea (BVD) virus isolation was negative.  These findings all pointed towards a diagnosis of colisepticaemia, with a secondary haemorrhagic syndrome. 

Salmonella Typhimurium 104 was recovered from a vaginal swab from a thin, downer cow on an Ayrshire farm. There had been problems with over-stocking on this farm and the previous month S. Typhimurium 104 was recovered after enrichment culture from the small intestine of a yearling calf. A case of human salmonellosis due to S. Typhimurium 104 was associated with this farm.

Alimentary tract disorders

Enteric colibacillosis due to infection with E coli K99 was diagnosed in a six-day-old calf from a suckler unit in northern Aberdeenshire mid-way through calving. Scouring at four to five days of age and three calf deaths were reported in a group of 150 cows. There was evidence of complete failure of colostral antibody absorption in the calf submitted for postmortem as judged by ZST testing.

Ayr examined a three-week-old Friesian heifer calf that died after an acute scour. The mucosa of the small intestine and the caecum were inflamed and intestinal contents were yellow. A heavy growth of E coli was recovered from the lung and small intestine and more limited growths were recovered from liver, spleen, kidney and mesenteric lymph node. Histopathology revealed a loss of villous epithelium but villi were of the expected height. The mucosa showed patchy degeneration with areas of collapse. Small, fine bacteria were seen in association with some of the remaining intact epithelium.  Peyer's patches were depleted but intact. These findings suggested an attaching, effacing E. coli enteritis.

A farm visit was carried out in conjunction with Animal Health to identify the possible source of an outbreak of disease due to Salmonella bovis morbificans on a farm in Dumfries and Galloway.  The farm carried 150 suckler cows.  None of the 70 cows housed in a cubicle shed were affected.  However 30 of the 80 out wintered cows became ill and required treatment with antibiotics.  One cow died, a further three aborted and two calves were stillborn.  The clinical signs varied from cows that were dull and anorexic to those with profuse scour and pyrexia.   No neonatal calves were affected.  Samples were taken from the water supply, the feed and the chicken and duck houses but no salmonellae were identified.  Two deer carcases were seen close to the field ten days before the outbreak began.  These were considered to be a possible source but they had been removed so were not available for sampling.  Advice was given on the zoonotic risk.

Reproductive tract conditions

Campylobacter fetus fetus was isolated from abortion material from two farms in Dumfries and Galloway.  In the first case cows returned to service three to four months after bulling.  A two centimetre foetus and placenta were submitted and the bacteria isolated.  On the second farm the submitted foetus was around seven months gestation.  This was the fourth abortion in three weeks.  The most likely source of infection on this farm was bought-in cows.  Both affected farms were dairies and using bulls alongside A.I.  The SAC VS recommended that they used A. I. alone.

An aborted foetus submitted from a Perthshire farm was the second abortion to occur during the spring-calving period.  Aspergillus fumigatus was cultured from foetal stomach contents.    Histopathological examination of lung found mononuclear cells with occasional multinucleate cells present within alveolar spaces and some bronchioles, while in the liver there was mild periportal infiltrate with occasional portal-portal bridging. These changes were consistent with the presence of an infectious process, and while lesions associated with A. fumigatus infections are usually restricted to the placenta, bronchopneumonia has occasionally been reported.

Nervous system disorders

Histological examination of the brain from a two-day-old Limousin calf revealed pathological lesions that suggested abnormal development. The calf was the third this year to be seen head shaking, inco-ordinated and unable to suckle.  The farmer reported similar problems in some calves the previous year. Changes were present in some folia of the cerebellum such as the absence and ectopic localization of Purkinje cells, slimming and increase of the cellularity in the molecular layer and cellular paucity in the granular layer. There were several mononuclear perivascular cuffs in the cerebrum and brainstem. BVD virus could cause such changes and although virus isolation was negative, the SAC VS advised assessment of the herd's BVD status.

Renal diseases

An eight-year-old Holstein cow from a Dumfries and Galloway herd stopped eating and lost condition one week before dying.  This was the third cow in the herd to show similar symptoms through the winter.  The bladder mucosa was thickened with discrete abscesses and the ureters contained pus.  One kidney was small and fibrosed while the other was swollen (figure 1).  The kidney capsules were adhered to the renal tissue.  Cystitis and pyelonephritis were diagnosed. 

Ayr reported a similar case.  In addition to the renal pathology there was peritonitis, consolidation of the left diaphragmatic lung lobe with miliary lesions and petechiae on the epicardium. A heavy growth of Arcanobacterium pyogenes was recovered from the kidneys and limited growths of the same organism were recovered from the lung, liver and spleen. Histopathology showed a chronic, active tubulo-nephritis with bacterial consolidation and abscessation. Chronic interstitial nephritis was also present in areas with affected tubules. This renal condition is reported as having a sporadic occurrence with a higher susceptibility in high-producing dairy herds.